A liquid crystal panel is manufactured by laminating two glass substrates together, sealing liquid crystal therebetween, cutting the glass substrates into a predetermined size, and then affixing a polarizing plate on a surface of one of the cut glass substrates. In the step of cutting the glass substrates, cullet produced from the cut surfaces may adhere to the surfaces of the glass substrates. If a polarizing plate is affixed in a state in which cullet adheres, bubbles present between the polarizing plate and the glass substrate deteriorates the display quality of the liquid crystal panel.
Patent Documents 1 to 4 are prior arts which disclose liquid crystal panel cleaning apparatuses for removing cullet adhering to surfaces of glass substrates. A liquid crystal panel cleaning apparatus disclosed in Japanese Patent Laying-Open No. 2002-244115 (Patent Document 1) includes a rotating head unit having an opposing surface parallel to a surface of a liquid crystal panel. The head unit includes a flat plate-like blade formed of a carbide material, and a flat end portion is formed at the edge of the blade.
A liquid crystal panel terminal cleaning apparatus disclosed in Japanese Patent Laying-Open No. 11-095242 (Patent Document 2) includes a positioning means for positioning a liquid crystal panel. A cullet removing apparatus for a liquid crystal glass substrate as disclosed in Japanese Patent Laying-Open No. 10-039282 (Patent Document 3) includes a knife driven by a motor to rotate on its own axis and revolve around an axis. A cleaning apparatus for a liquid crystal panel as disclosed in Japanese Patent Laying-Open No. 2000-015188 (Patent Document 4) includes a first unit in which a first suction fixing means and a second cleaning means are integrally formed, and a second unit in which a second suction fixing means and a first cleaning means are integrally formed.
FIG. 8 is a cross-sectional view schematically illustrating an operation of a conventional substrate cleaning apparatus. FIG. 9 is a side view schematically showing a contact state between a blade of the substrate cleaning apparatus shown in FIG. 8 and a glass substrate. FIG. 10 is a cross-sectional view schematically showing a cross section of the blade included in the substrate cleaning apparatus.
As shown in FIG. 8, cullet 60 adheres to an upper surface of a first glass substrate 50 laminated on an upper surface of a second glass substrate 70. A tip end portion 10a of a blade 10 of the substrate cleaning apparatus is in contact with the upper surface of first glass substrate 50. This blade 10 moves on the upper surface of first glass substrate 50 in a cleaning direction relative to first glass substrate 50 thereby removing cullet 60 from the upper surface of first glass substrate 50.
Therefore, if the parallelism between tip end portion 10a of blade 10 and first glass substrate 50 is not kept, as shown in FIG. 9, tip end portion 10a of blade 10 and first glass substrate 50 come into contact with each other locally at one side end of blade 10. As shown in FIG. 10, tip end portion 10a of blade 10 included in the substrate cleaning apparatus is processed to have an acute angle. Blade 10 is not easily deformed because it is formed of a carbide material.